Heat Sink

ABSTRACT

A heat sink comprises a frame having an axle sleeve, a motor axle having an shaft, a positioning unit securely around the axle sleeve and a rotating unit. The rotating unit is connected to the shaft and has a hub with a through hole. An axle is positioned at a top side of the hub corresponding to the flange of the through hole to receive the shaft. A connection element is fitted to the axle to securely sleeve the shaft. When fitting the shaft into the axle, the connection element is inserted into the through hole to secure around the shaft in order to securely position the shaft within the axle and securely assemble the hub to the shaft. Thus, the heat sink can be quickly, easily and precisely assembled.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat sink, and more particularly to aheat sink that can be more easily, precisely and securely assembled.

2. Description of the Related Art

Referring to FIG. 1, to assemble a conventional fan 11 of a heat sink,the shaft 12 of the motor axle is inserted into the axle sleeve 112 ofthe hub 111 of the fan 11.

The process of assembling the fan 11 to the shaft 12 includes, first,preparing a fan mold (not shown) to vertically receive the shaft 12 intothe space reserved in the axle sleeve 112. Next, a molten plastic isinjected into the mold, and then it is cooled down and the mold isremoved to obtain the shaft 12 of the fan 11 and simultaneously assemblethe shaft 12 to the hub 111 of the fan 11.

However, in the process of forming the fan 11 using a plastic injectionprocess and then assembling the fan 11 with the shaft 12 during the sameprocess, when the molten plastic material is injected in the injectionmolding process, the shaft 12 is pushed and may get misaligned. Thus,the center of axis of the hub 111 may not coincide with that of theshaft 12, and the fan 11 may not rotate smoothly and heat dissipationeffect may be poor. Correction of such an error would incur extra timeand labor due to complexity of the correction process which wouldsubstantially increase the overall cost.

FIG. 2 illustrates another conventional process of assembling the shaft32 of the motor axle and to the fan 31 of the heat sink 3. First, thefan 31 is formed, and then the shaft 32 of the motor axle is insertedinto the axle sleeve 312 and attached or glued therein to complete theassembly.

However, for implementing the process of inserting and adhering theshaft 32 of the motor axle in the axle sleeve 312 demands high precisionin the dimension of the axle sleeve 312 of the fan 31. Besides, duringthe assembly process, the shaft 32 must enter into the hub 311 forjointing there-with, which is difficult to ascertain, and therefore thisprocess more complicated.

SUMMARY OF THE INVENTION

Accordingly, in the view of the foregoing, the present inventionprovides a heat sink that can be more easily, precisely and securelyassembled. The heat sink of the present invention comprises a frame, amotor axle, a positioning unit and a rotating unit. The frame comprisesa base and an axle sleeve positioned on the base. The motor axlecomprises an axle positioned within the axle sleeve and a shaftpositioned on the top of the axle. The positioning element is securelypositioned around the axle sleeve. The rotating unit is rotatablypositioned covering the positioning element and jointed to the motoraxle. The rotating unit comprises a hub having a through hole at acentral region, an axle sleeve for receiving the shaft positioned on thetop of the hub and corresponds to the edge of the through hole, aconnection element positioned within the axle sleeve securing the shaft,a magnetic ring positioned at the inner flange of the hub that mutuallysense with the positioning element, and a plurality of bladesalternately positioned spaced apart around the outer periphery of thehub.

According to an aspect of the present invention, the through hole of thehub or the center of axis of the rotating unit coincides with that ofthe axle sleeve. The shaft of the motor axle is penetrated through theaxle sleeve from the top to the bottom to coordinate with the connectionelement positioned from the top to the bottom in the axle sleeve throughthe through hole. Thus, the shaft of the axle sleeve can be securelypositioned in the axle sleeve, the rotating unit can be securely jointedto the shaft, and thereby making the whole assembly process much moreeasy, precise, secure and fast.

BRIEF DESCRIPTION OF THE DRAWING

For a more complete understanding of the present invention, referencewill now be made to the following detailed description of preferredembodiments taken in conjunction with the following accompanyingdrawings.

FIG. 1 is a sectional side view of a conventional shaft of a heat sinkthat easily bias away from the hub.

FIG. 2 is a sectional side view of a conventional shaft of the heat sinktightly jointed to the hub.

FIG. 3 is an exploded view of a heat sink according to a first preferredembodiment of the present invention.

FIG. 4 is a sectional side view of a heat sink show including the Cshaped ring connection element according to the first preferredembodiment of the present invention.

FIG. 5 is a sectional side view of a heat sink including a metallic ringconnection element according to a second preferred embodiment of thepresent invention.

FIG. 6 is a sectional view of an shaft having a corrugated surfaceaccording to a third preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 3 and 4, the heat sink 2, according to the firstpreferred embodiment of the present invention, comprises a frame 21, amotor axle 22 positioned in the frame 21, a positioning unit 23 and arotating unit 24 rotatably positioned over the positioning unit 23.

The frame 21 comprises a base 211 and an axle sleeve 212 positioned onthe base 211 to receive the motor axle 22. The axle sleeve 212 comprisesfour elastic pillars 213 circularly positioned with gaps there-between.The distal end of each pillar 213 is bent right angle towards the motoraxle 22. The four pillars 213 can be obliquely bent outwards and can berestored back to upright position.

The motor axle 22 comprises an axle 221 positioned within the axlesleeve 212, and a shaft 222 positioned on a top of the axle 221 andconnected to the rotating unit 24 at a distal end thereof. The top ofthe axle 221 is pressed by the bent distal end of the pillar 213 of theaxle sleeve 212. The shaft 222 has a groove 223 formed at a distal endthereof.

The positioning unit 23 comprises a ring set 23 positioned around theaxle sleeve 212 of the frame 21. The rotating unit 24 is rotatablepositioned covering the outer periphery of the positioning unit 23 andjointed to the shaft 222 of the motor axle 22. The rotating unit 24comprises a hub 241 having a through hole 242 at a central regionthereof; an axle 243 for receiving the shaft 222 from the top to thebottom, positioned on the top of the hub 241 corresponding to the flangeof the through hole 242, a connection element 247 passing from the topto the bottom through the through hole 242 supported by the axle 243 andsecurely locked to the shaft 222, a magnetic ring 248 positioned at ainner side of the hub 241 and capable of mutually sensing with thepositioning unit 23, and a plurality of blades 249 alternatelypositioned spaced apart around the outer periphery of the hub 241. Inthis embodiment, the connection element 247 comprises an elasticC-shaped buckling ring.

The axle 243 of the rotating unit 24 comprises a sleeve portion 244jointed to the top side of the hub 241, and a sidewall 245 horizontallyextending from the sleeve portion 244 towards the shaft 222 into thegroove 223 to hold or support the connection element 247. The sidewall245 forms an axle hole 246 communicating with the through hole 242 ofthe hub 241 for facilitating penetration of the shaft 222 there-through.

To assemble the heat sink 2, the pillars 213 of the axle sleeve 212 areforcedly bent outwards for receiving the motor axle 22, and thenrestored back to upright position for securely covering the surroundingsurface and the top surface of the axle 221 of the motor axle 22. Next,the rotating unit 24 is positioned covering the positioning unit 23 suchthat the shaft 222 of the motor axle 22 penetrates into the axle 243from the bottom to the top through the axle hole 246, and the sidewall245 of the axle 243 protrudes to support against the groove 223 of theshaft 222 to correspondingly secure the position of the rotating unit 24with the other elements, such as the frame 21 and the positioning unit23. Next, the connection element 247 is inserted into the through hole242 of the hub 241 until the connection element 247 is lodged into thegroove 223 and supported on the axle 243 to securely assemble the shaft222 to the hub 241 of the rotating unit 24 to complete assembly of theheat sink 2.

When the electric power is supplied to the heat sink 2, the coil set 231of the positioning unit 23 generates the alternate magnetic field due tothe magnetic element 248 of the rotating unit 24 so that the magneticelement 248 rotates to smoothly rotate the rotating unit 24 along theshaft 222 and thereby create air flow to dissipate heat.

Accordingly, the heat sink 2 of the present invention described abovehas at least the following advantages.

1. Easy and convenient to assemble: To assemble the shaft 222 of themotor axle 22 to the hub 241 of the rotating unit 24, the shaft 222 isinserted into the axle 243 through the axle hole 246, and then theconnection element 247 is inserted through the through hole 242 untilthe connection element 247 lodges into the groove 223 to securelyassemble the shaft 222 to the hub 241 of the rotating unit 24.

Thus, the shaft 222 has the same rotation shaft as that of the hub 241.By securing the connection element 247 into groove 223 of the shaft 222via the axle hole 242 of the hub 241, the heat sink 2 can be accuratelyassembled. Thus, the heat sink can be easily and precisely assembled andthereby overcome the defects of the conventional heat sink 1 describedabove with reference to FIG. 1, where during the plastic injection moldprocess for forming the fan 11 of the conventional heat sink 1, theshaft 12 can easily misalign from the center of shaft of the hub 111,and to correct the error, more complex process is required. Besides, theshaft 32 of the conventional heat sink 3, as shown in FIG. 2, has to befitted into the hub 311, this sort of assembly process is difficult tocontrol and inconvenient.

2. Precise assembly: After forming the hub 241 and the motor axle 22,the connection element 247 is inserted into the through hole 242 untilthe connection element 247 fits into the groove 223 of the axel 22 andis supported on the sidewall 245 of the axle 243 to easily and preciselyassemble the hub 241 to the shaft 222. Thus, the center of axis of theshaft 222 can precisely coincide with that of the hub 241. The processof assembling the heat sink is much more easier and precise compared tothat of the conventional heat sink 1 described above with reference toFIG. 1, where during the plastic injection process for forming the fan11 of the conventional heat sink 1, the shaft 12 can easily misalignfrom the center of shaft of the hub 111.

3. More secured assembly: The groove 223 of the shaft 222 is adoptedreceive the connection element 247 and the axle 243 of the rotating unit24 is adopted to securely support the connection element 247 in order tosecurely assemble the hub 241 to shaft 222.

4. Smooth operation to provide better heat dissipation effect: Asdescribed above, groove 223 of the shaft 222 is adopted receive theconnection element 247 and the axle 243 of the rotating unit 24 isadopted to securely support the connection element 247 in order tosecurely assemble the hub 241 to shaft 222. Thus, the center of axis ofthe shaft 222 can precisely coincide with that of the hub 241 so thatthe rotating unit 24 rotates smoothly and steadily to promote air flowand thereby improve the heat dissipation effect and overcome the defectof the conventional heat sink 1 described above.

FIG. 5 shows a heat sink 2 according to the second preferred embodimentof the present invention, which is similar to that of the firstembodiment described above except for the sectional side of the distalend of the shaft 222 of the motor axle 22 comprises a reverse T shapeand the connection element 247 comprises a metallic ring to rivet withthe shaft 222 of the motor axle 22.

Therefore, after fitting the shaft 222 into the axle 243, the connectionelement 247 may be inserted through the through hole 242 of the hub 241until it securely rivets with the groove 223 of the shaft 222.

FIG. 6 shows an shaft 222 of a heat sink according to the thirdpreferred embodiment of the present invention, which is similar to thatof the first preferred embodiment described above except for the shaft222 comprises a corrugated surface 224 to increase the contact surfacearea between the shaft 222 and the connection element 247 for moresecurely assembling the connecting element 247 to the shaft 222.

In summary, the heat sink 2 of the present invention comprises the hub241 having the through hole 242, the shaft 222 of the motor axle 22 isfitted into the axle 243 from the bottom to the top and the connectionelement 247 is fitted into the axle 243 by inserting the connectionelement 247 through the through hole 242 to securely position the shaft222 of the motor axle 22 within the axle 243, and precisely, easily andsecurely assemble the rotating unit 24 to the shaft 222 and therebyquickly complete the assembly of the heat sink.

While the invention has been described in conjunction with a specificbest mode, it is to be understood that many alternatives, modifications,and variations will be apparent to those skilled in the art in light ofthe foregoing description. Accordingly, it is intended to embrace allsuch alternatives, modifications, and variations in which fall withinthe spirit and scope of the included claims. All matters set forthherein or shown in the accompanying drawings are to be interpreted in anillustrative and non-limiting sense.

1. A heat sink, comprising: a frame, comprising a base and an axlesleeve; a motor axle, comprising an axle positioned in said axle sleeveand an shaft positioned on a top surface of said axle; a positioningunit, coaxially secured around said axle sleeve; a rotating unit,rotatably positioned covering said positioning unit and jointed to saidshaft of said motor axle, comprising a hub having a through hole at acentral region, an axle positioned at a top side thereof andcorresponding to a flange of said through hole for receiving said shaft;a connection element, positioned within said axle and fitted around saidshaft; a magnetic ring, positioned within said hub, for mutually sensingsaid positioning unit; and a plurality of blades, alternately positionedspaced apart around an outer periphery of said hub.
 2. The heat sinkaccording to claim 1, wherein said axle of said rotating unit comprisesa sleeve portion connected to said hub and a sidewall extending from abottom flange of said sleeve portion towards said shaft, said sidewallforms an axle hole coinciding with said through hole of said hub so thatsaid shaft penetrates there-through.
 3. The heat sink according to claim1, wherein said shaft of said motor axle has an indented groove forreceiving said connection element of said rotating unit, and saidconnection element comprises an elastic C-shape buckle.
 4. The heat sinkaccording to claim 1, wherein said connection element of said rotatingunit comprises a metallic ring to rivet to said shaft of said motoraxle.
 5. The heat sink according to claim 4, wherein said shaft of saidmotor axle comprises a corrugated surface.
 6. The heat sink according toclaim 1, wherein said axle sleeve of said frame comprises a plurality ofelastic pillars circularly positioned thereon with gaps there-between,and wherein a distal end of each pillar is bent at a right angle towardssaid motor axle.